关键词: 低热水泥;混凝土;早龄期;导热系数;养护温度;水化度;

Abstract: In order to study the thermal conductivity evolution law of low-heat cement concrete at early-age under a general temperature environment, the hydration heat and thermal conductivity experiment of low-heat cement under different curing temperature and water-cement ratios were designed and carried out.According to the experiment results, the effect mechanism of curing temperature on thermal conductivity of low-heat cement concrete was analyzed, and the prediction model of thermal conductivity considering temperature effect was established.The results showed that the high temperature curing increased the hydration heat and heat release rate of low-heat cement at early-age, and the hydration degree under standard curing had a hysteresis compared to high temperature curing.The thermal conductivity increased first and then decreased with the increasing of curing temperature, and the greater the water-cement ratio was, the lower thermal conductivity could be.The proposed prediction model was verified by experiments and it was found that the thermal conductivity decreased with the increasing of hydration degree.When the hydration degree was 0.39～0.41,the critical peak value of thermal conductivity was 1.51～1.45 W/(m·K).The research results can provide a theoretical support for accurate calculation of temperature field and temperature control of low-heat cement concrete at early-age.

Key words: low-heat cement; concrete; early-age; thermal conductivity; curing temperature; hydration degree;